The present invention relates to emergency pull stations, such as pull stations for triggering fire alarms.
In known fire alarm pull stations, a lever is provided which can be manually pivoted or depressed to set off a local or centralized fire alarm. Such fire alarms are typically present in buildings such as schools, hospitals, and the like. The alarm pull stations mount on a wall and are typically color coded to be easily recognizable in an emergency.
Such pull stations are manufactured for example by Pittway Corporation, NOTIFIER Division, such as models: NBG-10 series Non-Coded Manual Fire Alarm Station, BGX-101L Addressable Manual Pull Station, BNG and BRG series Manual Fire Alarm Stations or LNG Double-Action Manual Fire Alarm Station.
To prevent vandalism or nuisance alarms involving such pull stations, the pull stations are configured to lock in the alarm state once the activation lever is depressed or otherwise placed in an alarm state. To reset a pull station, a key is required to release the lever to its initial, non-alarm state.
According to a first aspect of the invention, a pull station for an alarm system includes features adapted to enhance manufacturing, assembly and effectiveness of the pull station. The pull station includes a back plate or base plate which carries an alarm switch on a front side and a terminal block on a back side.
A cover is hingedly connected to the back plate. The cover carries a handle slidably held thereto that is accessible through an opening in a front wall of the cover. The handle is biased upwardly and when forcibly pulled downwardly, activates the alarm switch.
A latch is carried by the handle. The latch moves with the handle and engages an abutment of the back plate to prevent upward retraction of the handle, when the handle has reached its downward, alarm position.
A lock is mounted in an opening in the front wall of the cover. When locked, the lock fixes the cover to the back wall in a closed configuration. Once the handle is pulled to its alarm position, the lock must be unlocked, the cover opened and the latch disengaged from the abutment to retract the handle to reset the pull station.
The handle includes a body portion having a switch activator facing rearwardly thereof. The switch activator includes a structure which captures a switch lever of the alarm switch such that sliding movement of the body portion changes the state of the alarm switch. Additionally, a contoured ramp of the structure acts to reset the switch lever when the cover is pivotally closed to the back plate.
The body portion includes outwardly extending tabs on a top end thereof, on opposite lateral sides of the body portion, which are slidably captured in side channels of the cover. The handle also includes an extension portion connected to, such as being formed with, a lower end of the body portion. The extension portion includes a front wall portion having an elongated slot, elongated in a direction of sliding movement of the body portion.
According to different fire codes, pull stations must have handles which operate in either a single action, such as a xe2x80x9cpull downxe2x80x9d, mode or in a double action, such as a xe2x80x9cpress in and then pull downxe2x80x9d, mode. In a first, single action, configuration, an anchor portion having an outwardly directed stop portion is connected to a rear side of the cover front wall, the anchor portion having a circular base portion that penetrates the elongated slot. The stop portion overlies the front wall portion of the extension portion on lateral sides of the slot to capture the extension portion onto the cover front wall but which allows sliding of the extension portion with respect thereto.
In an alternate double action configuration, the anchor portion is mounted with the stop portion located between the extension portion and the front wall of the cover. The stop portion fits into stop grooves formed on the front side of the extension portion. In this orientation, the stop portion serves as a blocking member which abuts side walls of the stop grooves on a front surface of the extension portion and prohibits the handle from sliding downwardly unless the handle is first pushed in and then slid downwardly.
When pushed in, the stop portion clears the stop grooves and the handle can be slid downwardly. The spring loaded latch provides a resilient opposition or xe2x80x9cfeelxe2x80x9d to pushing in the handle.
The extension portion includes substantially parallel side walls, extending from the extension portion front wall rearwardly. The latch is rotatably mounted between, and to, the side walls. A torsional spring biases the latch to rotate toward an engagement position, with a latch tip of the latch pressed against the back plate.
The back plate includes a stepped surface extending forwardly thereof and in registration with the latch. The stepped surface includes a forward surface parallel to a back surface of the front wall of the cover and arranged at a first distance from the back surface of the front wall of the cover, to be pressed by the latch tip. The stepped surface has a rearward surface parallel to the back surface of the front wall of the cover and arranged at a second distance from the back surface of the front wall of the cover, the second distance greater than the first distance. A perpendicular surface is formed between the forward and rearward surfaces.
During sliding of the handle with respect to the cover and back plate, the latch tip slides on the forward surface and, under force from the torsional spring, moves between the forward and rearward surfaces. In this position, an end of the latch, that is adjacent to the latch tip, can abut the perpendicular surface. The perpendicular surface, by abutment against the latch end, prohibits the latch element from proceeding in a reverse direction, which in turn prohibits the handle from being slid in a reverse direction.
In order to reset the handle to its elevated position, the cover must be unlocked and opened. When the cover is opened, the latch will disengage the stepped wall and the handle will be automatically retracted upwardly by the spring. When the cover is subsequently closed against the base plate, the latch will be forced to resiliently rotate to assume its position pressed against the forward surface of the stepped wall.
The exemplary embodiments of the invention reduce or eliminate fasteners in the assembly and include the ability to assemble the components in two configurations for two operating modes: a handle slide down only mode, and a handle press inwardly and then slide down mode. The pull station can be configured and assembled in either configuration without requiring different parts or fasteners. The cover is connected to the base plate without use of fasteners. The spring loaded latch is also snap fit to the handle, without requiring fasteners.
The handle is assembled to the cover without fasteners. In the first configuration, the handle is slid onto the cover at a top end of the handle, with the handle at about 90xc2x0 to the cover, and then the handle is pivoted toward the cover 90xc2x0 and secured by the anchor member with the stop portion overlying the extension portion. The handle is thus attached for sliding movement with respect to the back plate.
In the alternate configuration, the handle is slid onto the cover at the top end of the handle with the handle at 90xc2x0 to the cover. The anchor member is comparatively oriented turned over and rotated 180xc2x0 compared to the first configuration. The anchor member is attached to the cover. The handle is then pivoted toward the cover by about 90xc2x0.
The extension portion is guided by the anchor member for sliding movement, but not restrained against the cover, by the anchor member. The extension portion is urged toward the cover by the resilient pressing of the latch against the back plate.
The electric terminals which are mounted to a back of the pull station, are configured to be pressed in place using barbed legs of a U-shaped body. The terminals are set at a standard 0.375 inch spacing and each provides a solder lug, a screw terminal and a pin connector. The screw terminal is configured to accept a two wire lead. The U-shaped body provides an interior region or space for the threaded shaft of the screw terminal to enter.
According to another aspect of the invention, the handle can be composed of transparent or translucent material, such as plastic material. The switch module can include an LED status annunciator located behind the handle. A blinking of the LED for example can indicate a xe2x80x9creadyxe2x80x9d condition of the pull station.
According to another aspect of the invention, a PC board inside the housing can be mounted according to two orientations, to avoid covering the housing mounting holes for mounting the housing to an electrical box or other mounting structure or surface.
Also, the cover of the module includes the warning message, such as the word xe2x80x9cFIRExe2x80x9d, molded as a recess into the cover and the word is hot stamped in white within the recess.